JP6888128B1 - Vapor deposition mask - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a thin-film deposition mask capable of suppressing adhesion of fibers to a thin-film deposition mask. A metal vapor deposition mask 10. A lattice structure 10M having a front surface 10F and a back surface, and having a two-dimensional mesh shape separating a plurality of mask holes 10H connecting a large opening HL located on the front surface 10F and a small opening located on the back surface. It has a structure of 10M. The arithmetic mean roughness Ra conforming to JIS B 0601: 2013 at the boundary of large openings HL adjacent to each other on the surface 10F is 1.35 μm or less, and the maximum height Rz conforming to JIS B 0601: 2013 at the boundary. However, it is 6.8 μm or less. [Selection diagram] Fig. 3

Description

The present invention relates to a vapor deposition mask.

Vacuum deposition using a vapor deposition mask is used to form the organic EL element included in the organic EL device. The vapor deposition mask is formed from a very thin metal sheet. The thickness of the mass-produced vapor deposition mask includes, for example, a portion having a thickness of 50 μm or less. When the vapor deposition mask is conveyed, the vapor deposition mask is housed in a case for the vapor deposition mask in order to suppress deformation of the vapor deposition mask (see, for example, Patent Document 1).

Utility model registration No. 3207895

By the way, the vapor deposition mask is housed in the vapor deposition mask case in a state of being sandwiched between a pair of dust-free papers in the thickness direction of the vapor deposition mask. When the vapor deposition mask is housed in the vapor deposition mask case, when the vapor deposition mask case is conveyed, and when the vapor deposition mask is taken out from the vapor deposition mask, friction occurs between the vapor deposition mask and the dust-free paper. The friction generated between the vapor deposition mask and the dust-free paper causes the fibers caught on the surface of the vapor deposition mask to adhere to the vapor deposition mask as foreign matter.

An object of the present invention is to provide a thin-film deposition mask capable of suppressing the adhesion of fibers to the thin-film deposition mask.

The vapor deposition mask for solving the above problems is a metal vapor deposition mask, which has a lattice structure having a front surface and a back surface, and has a large opening located on the front surface and a small opening located on the back surface. It has the lattice structure having a two-dimensional network that separates a plurality of mask holes to be connected, and has an arithmetic mean roughness Ra according to JIS B 0601: 2013 at the boundary of large openings adjacent to each other on the surface. It is .35 μm or less, and the maximum height Rz in accordance with JIS B 0601: 2013 at the boundary is 6.8 μm or less.

The surface roughness of the metal plate for forming the vapor deposition mask is usually set sufficiently small to obtain the adhesion between the metal plate and the resist. On the other hand, the surface roughness of the metal plate after the mask holes are formed, that is, the surface roughness of the vapor-deposited mask has a large step by the amount of the step of the mask hole. Since the distance between the large openings on the front surface is shorter than the distance between the small openings on the back surface, the step on the front surface per unit length tends to be larger than the step on the back surface per unit length. In other words, the surface of the metal plate, which was sufficiently flat before the processing of the mask holes, remains less on the front surface of the lattice structure than on the back surface, and the surface of the lattice structure is wide because the area of the mask holes that causes the step is wide. Then, the surface roughness becomes larger than that of the back surface. In this respect, if the arithmetic mean roughness Ra on the surface of the lattice structure having a large surface roughness is 1.35 μm or less, it is possible to suppress the adhesion of fibers on both the front surface and the back surface of the lattice structure. .. As a result, it is possible to prevent the fibers from adhering to the vapor deposition mask.

The maximum height Rz of the roughness curve is the sum of the maximum mountain height Rp and the maximum valley depth Rv. Therefore, the larger the maximum height Rz, the more likely the surface of the vapor deposition mask has a peak portion that is caught by the fibers forming the dust-free paper, and a valley portion into which the fibers are fitted. In this respect, if the maximum height Rz is 6.8 μm or less, the peak portion located on the surface of the vapor deposition mask has a height that makes it difficult for the fiber to get caught, and the valley portion has a depth that makes it difficult for the fiber to fit. It is possible to have.

The vapor deposition mask includes a recess located on a lattice line of the lattice structure and a top portion located at a lattice point of the lattice structure and a portion where the recesses are connected to each other. The boundary may be constructed.

In the vapor deposition mask, the top may be flat. According to this configuration, the gaps between the large openings located diagonally in the large openings remain unetched, so that the top is flat, so that the fibers are less likely to adhere.

In the vapor deposition mask, the lattice structure includes a first lattice line having a thick line width on the surface and a second lattice line having a narrow line width on the surface, and the first lattice line and the second lattice line. Consists of the boundary, and the arithmetic mean roughness Ra conforming to JIS B 0601: 2013 at the first grid line on the surface conforms to JIS B 0601: 2013 at the second grid line on the surface. It may be smaller than the arithmetic mean roughness Ra.

According to the above configuration, the arithmetic average roughness Ra of the first grid line, which has a larger contact area with the dust-free paper than the second grid line, is smaller than the arithmetic average roughness Ra of the second grid line. When friction occurs with the dust-free paper, it is possible to suppress the detachment of the fibers derived from the dust-free paper.

According to the present invention, it is possible to prevent fibers from adhering to the vapor deposition mask.

The plan view which shows the structure in the mask apparatus which comprises the vapor deposition mask of 1st Embodiment. The perspective view which shows the structure in the vapor deposition mask of 1st Embodiment. The plan view which shows the structure seen from the viewpoint facing the surface in the thin-film deposition mask of 1st Embodiment. The plan view which shows the structure seen from the viewpoint facing the back surface of the vapor deposition mask of 1st Embodiment. The cross-sectional view which shows the structure of the vapor deposition mask of 1st Embodiment. The graph which shows typically the height profile in the surface of the vapor deposition mask along the straight line connecting the point A1 and the point A4 shown in FIG. The process chart which shows the rolling process for manufacturing the base material for a vapor deposition mask. The process chart which shows the heating process for manufacturing the base material for a vapor deposition mask. The process drawing which shows the etching process for manufacturing the vapor deposition mask. The process drawing which shows the etching process for manufacturing the vapor deposition mask. The process drawing which shows the etching process for manufacturing the vapor deposition mask. The process drawing which shows the etching process for manufacturing the vapor deposition mask. The process drawing which shows the etching process for manufacturing the vapor deposition mask. The process drawing which shows the etching process for manufacturing the vapor deposition mask. A table showing the measurement results and evaluation results of the vapor deposition masks of Examples and Comparative Examples. The plan view which shows the structure seen from the viewpoint facing the surface in the thin-film deposition mask of 2nd Embodiment. The plan view which shows the structure seen from the viewpoint facing the back surface of the vapor deposition mask of 2nd Embodiment. The graph which shows typically the height profile in the surface of the vapor deposition mask along the straight line connecting the point B1 and the point B2 shown in FIG. The graph which shows typically the height profile in the surface of the vapor deposition mask along the straight line connecting the point C1 and the point C2 shown in FIG. A table showing the measurement results and evaluation results of the vapor deposition masks of Examples and Comparative Examples.

[First Embodiment]
A first embodiment of the vapor deposition mask will be described with reference to FIGS. 1 to 15. Hereinafter, a mask device, a thin-film mask, a method for manufacturing a base material for a thin-film mask, a method for manufacturing a thin-film mask, and an embodiment will be described in order.

[Mask device]
The masking apparatus will be described with reference to FIG.
As shown in FIG. 1, the mask device 100 includes a frame 101 and a plurality of thin-film deposition masks 10. In the example shown in FIG. 1, the mask device 100 includes two thin-film deposition masks 10, but the mask device 100 may include one thin-film deposition mask 10 or three or more thin-film deposition masks 10. May be good. The frame 101 has a rectangular frame shape capable of supporting a plurality of vapor deposition masks 10. The frame 101 is attached to a vapor deposition apparatus for performing vapor deposition. The frame 101 has a frame hole 101H penetrating the frame 101 over almost the entire range where each vapor deposition mask 10 is located.

The vapor deposition mask 10 includes a pattern region 10a and a peripheral region 10b. The peripheral region 10b is an region surrounding the pattern region 10a. In the example shown in FIG. 1, the vapor deposition mask 10 has three pattern regions 10a. The vapor deposition mask 10 may have two or less pattern regions 10a, or may have four or more pattern regions 10a. When the vapor deposition mask 10 has a plurality of pattern regions 10a, the plurality of pattern regions 10a are at least a region arranged along the length direction of the vapor deposition mask 10 and a region arranged along the width direction of the vapor deposition mask 10. One may be included.

Each vapor deposition mask 10 has a strip shape extending along the length direction. Within the peripheral region 10b of each vapor deposition mask 10, a pair of portions sandwiching the plurality of pattern regions 10a in the direction in which the vapor deposition mask 10 extends are fixed to the frame 101, respectively. The vapor deposition mask 10 is fixed to the frame 101 by adhesion, welding, or the like.

[Evaporation mask]
The vapor deposition mask will be described with reference to FIGS. 2 to 6. FIG. 2 shows an enlarged part of the vapor deposition mask 10 attached to the above-mentioned mask device.

The vapor deposition mask 10 shown in FIG. 2 is made of metal. The vapor deposition mask 10 is formed of, for example, an iron-nickel alloy. The vapor deposition mask 10 is preferably formed from Invar among iron-nickel alloys. The vapor deposition mask 10 has, for example, a thickness T of 10 μm or more and 50 μm or less. The pattern region 10a is a region in which a plurality of mask holes 10H are formed. On the other hand, the peripheral region 10b is a region in which the mask hole 10H is not formed. The vapor deposition mask 10 has a DL in the length direction and a DW in the width direction. The width direction DW is a direction orthogonal to the length direction DL.

The vapor deposition mask 10 is housed in the vapor deposition mask case when the vapor deposition mask 10 is transported. At this time, the vapor deposition mask 10 is housed in the vapor deposition mask case in a state of being sandwiched between a pair of dust-free papers in the thickness direction of the vapor deposition mask 10. When the vapor deposition mask 10 is housed in the vapor deposition mask case, when the vapor deposition mask case is conveyed, and when the vapor deposition mask 10 is taken out from the vapor deposition mask case, friction occurs between the vapor deposition mask 10 and the dust-free paper.

FIG. 3 shows a planar structure in a part of the pattern region 10a viewed from a viewpoint facing the plane on which the vapor deposition mask 10 spreads.
As shown in FIG. 3, the vapor deposition mask 10 has a lattice structure 10M having a front surface 10F and a back surface 10R (see FIG. 4). The lattice structure 10M has a two-dimensional mesh shape that separates a plurality of mask holes 10H connecting a large opening HL located on the front surface 10F and a small opening HS (see FIG. 4) located on the back surface 10R (see FIG. 4). doing. The plurality of mask holes 10H are arranged in a grid pattern along the length direction DL and the width direction DW.

The surface 10F of the lattice structure 10M includes a depression located on the lattice line of the lattice structure 10M and a top portion located at a lattice point of the lattice structure 10M and connecting the depressions to each other. The depression located on the surface 10F and the top form the boundary of the large opening HL adjacent to each other on the surface 10F. In the example shown in FIG. 3, the large openings HL adjacent to each other have a part of the edge in contact with each other in both the length direction DL and the width direction DW. Further, when a plurality of large opening HLs are formed by wet etching, a part of the region etched to form each large opening HL and a large opening HL adjacent to the large opening HL are formed. A part of the etched area is connected. As a result, a recess located on the lattice line of the lattice structure 10M is formed.

Each mask hole 10H has a central opening HC. Like the plurality of mask holes 10H, the plurality of central opening HCs are arranged in a grid pattern along the length direction DL and the width direction DW. The central opening HC is smaller than the large opening HL when viewed from the viewpoint facing the surface 10F. In the mask hole 10H, the cross-sectional area along the plane parallel to the surface 10F gradually decreases along the direction from the large opening HL to the central opening HC. In the mask hole 10H, the portion from the large opening HL to the central opening HC has an inverted pyramid shape when viewed from the viewpoint facing the surface 10F. The portion from the large opening HL to the central opening HC is a large hole provided in the mask hole 10H. In this embodiment, the edges of each large opening HL have a substantially square shape. The edge of each central opening HC also has a substantially square shape.

FIG. 4 shows a planar structure in a part of the pattern region 10a seen from the viewpoint facing the back surface 10R.
As shown in FIG. 4, each mask hole 10H has a small opening HS that opens to the back surface 10R. The small opening HS has a substantially square shape when viewed from a viewpoint facing the back surface 10R. The small opening HS is larger than the central opening HC. In the mask hole 10H, the cross-sectional area along the plane parallel to the back surface 10R gradually decreases along the direction from the small opening HS to the central opening HC. In the mask hole 10H, the portion from the small opening HS to the central opening HC has an inverted weight stand shape when viewed from the viewpoint facing the back surface 10R. The portion from the small opening HS to the central opening HC is a small hole provided in the mask hole 10H.

The above-mentioned vapor deposition mask 10 satisfies the following condition 1.
(Condition 1) The arithmetic mean roughness Ra according to JIS B 0601: 2013 at the boundary of large openings HL adjacent to each other on the surface 10F is 1.35 μm or less.

The surface roughness of the metal plate for forming the vapor deposition mask 10 is usually set sufficiently small to obtain the adhesion between the metal plate and the resist. On the other hand, the surface roughness of the metal plate after the mask hole 10H is formed, that is, the surface roughness of the vapor deposition mask 10 is increased by the amount of the step formed by the mask hole 10H. Since the distance in the gap between the two large openings HL on the front surface 10F is shorter than the distance in the gap between the two small openings HS on the back surface 10R, the step on the front surface 10F per unit length is per unit length. It tends to be larger than the step on the back surface 10R of. In other words, the metal plate that was sufficiently flat before the processing of the mask hole 10H remains less on the front surface of the vapor deposition mask 10 than on the back surface after processing, and the area of the mask hole 10H that causes a step is wide. The surface roughness of the front surface 10F of the lattice structure 10M is larger than that of the back surface 10R. In this respect, if the arithmetic mean roughness Ra on the surface 10F of the lattice structure 10M having a large surface roughness is 1.35 μm or less, the adhesion of fibers is suppressed on both the front surface 10F and the back surface 10R of the lattice structure 10M. It becomes possible.

The arithmetic mean roughness Ra under condition 1 is a roughness obtained when the cutoff value of the λs contour curve filter is set to 2.5 μm and the cutoff value of the λc contour curve filter is set to 250 μm. The arithmetic mean roughness of the curve.

Further, the vapor deposition mask 10 satisfies the following condition 2.
(Condition 2) The maximum height Rz in accordance with JIS B 0601: 2013 at the boundary of the large opening HL is 6.8 μm or less.

The maximum height Rz of the roughness curve is the sum of the maximum mountain height Rp and the maximum valley depth Rv. Therefore, the larger the maximum height Rz, the more likely the surface 10F of the vapor deposition mask 10 has a peak portion that is caught by the fibers forming the dust-free paper, and a valley portion into which the fibers are fitted. In this respect, when the maximum height Rz is 6.8 μm or less, the peak portion located on the surface 10F of the vapor deposition mask 10 has a height that makes it difficult for the fiber to get caught, and the valley portion makes it difficult for the fiber to fit. It is possible to have a depth.

The maximum height Rz under condition 2 is the contour obtained when the cutoff value in the λs contour curve filter is set to 2.5 μm and the cutoff value in the λc contour curve filter is set to 250 μm, as in condition 1. It is the maximum height of the roughness curve which is a curve.

Further, it is more preferable that the vapor deposition mask 10 satisfies the following condition 3.
(Condition 3) The top portion located at the lattice point of the lattice structure 10M is a plane.
In the vapor deposition mask 10, the gaps between the large openings HL located in the diagonal direction of the large opening HL remain without being etched, so that the top is flat, so that the fibers are less likely to adhere.

FIG. 5 shows the structure of the vapor deposition mask 10 along a cross section orthogonal to the surface 10F of the vapor deposition mask 10.
As shown in FIG. 5, each mask hole 10H includes a large hole 10HL and a small hole 10HS. The large hole 10HL has a shape that tapers from the front surface 10F to the back surface 10R. The small hole 10HS has a shape that tapers from the back surface 10R to the front surface 10F. The connecting portion between the large hole 10HL and the small hole 10HS is the central opening HC. Each foramen magnum 10HL is in contact with another adjacent foramen magnum 10HL in the foramen magnum HL.

FIG. 6 schematically shows the height profile of a part of the surface 10F of the vapor deposition mask 10. In FIG. 6, for convenience of explaining the height profile of the surface 10F, the height difference included in the height profile is exaggerated.

The height profile shown in FIG. 6 is a height profile along a straight line LA connecting the points A1 and A4 in FIG. The broken line shown in FIG. 6 indicates the average height of the surface 10F in the region targeted for analysis of the height profile. The straight line LA includes points A2 and A3 in addition to points A1 and A4. Each point A1, A2, A3, A4 is surrounded by four large opening HLs when viewed from a viewpoint facing the surface 10F of the vapor deposition mask 10.

As shown in FIG. 6, the height profile in the straight line LA has a maximum value at each point A1, A2, A3, A4. On the other hand, the height profile in the straight line LA has a local minimum value at a position where the distances from two adjacent points are approximately equal. The vapor deposition mask 10 is manufactured by wet etching of a substrate for a vapor deposition mask. At this time, the portions where the points A1, A2, A3, and A4 are located are the most etched among the vapor deposition mask base materials because the distance from the center of the large opening HL in the plan view facing the surface 10F is large. It is a part that is difficult to do. Therefore, the height is the highest at each point A1, A2, A3, A4. On the other hand, the portion located between the points adjacent to each other is the portion where the two large opening HLs are in contact with each other, and thus is the portion most easily etched. Therefore, the height is the lowest at a value where the distances from two adjacent points are almost equal.

[Manufacturing method of base material for vapor deposition mask]
A method for producing a base material for a vapor deposition mask used for producing the vapor deposition mask 10 will be described with reference to FIGS. 7 and 8. In the following, the manufacturing method using rolling and the manufacturing method using electrolysis will be illustrated separately. First, a manufacturing method using rolling will be described, and then a manufacturing method using electrolysis will be described. 7 and 8 show a manufacturing method using rolling.

As shown in FIG. 7, in the manufacturing method using rolling, first, a base material 1a formed from an iron-nickel alloy such as Invar is prepared, and the base material 1a extends in the length direction DL. Next, the base metal 1a is conveyed toward the rolling apparatus 50 so that the DL in the length direction of the base metal 1a and the conveying direction for conveying the base metal 1a are parallel to each other. The rolling apparatus 50 includes, for example, a pair of rolling rollers 51 and 52, and the base metal 1a is rolled by the pair of rolling rollers 51 and 52. As a result, the base material 1a is stretched in the length direction DL, so that the rolling material 1b is formed. By cutting both ends of the rolling material 1b in the width direction, the dimensions of the rolling material 1b in the width direction DW are adjusted. The rolling material 1b may be handled, for example, in a state of being wound around the core C, or may be handled in a state of being stretched into a strip shape. The thickness of the rolling material 1b is, for example, 10 μm or more and 50 μm or less. It is also possible to roll the base metal 1a using a plurality of pairs of rolling rollers. FIG. 7 illustrates a method of rolling the base metal 1a using a pair of rolling rollers.

Next, as shown in FIG. 8, the rolling material 1b is conveyed to the annealing device 53. The annealing device 53 heats the rolling material 1b while pulling it in the length direction DL. As a result, the residual stress accumulated in the rolling material 1b is removed from the inside of the rolling material 1b, and the substrate 1 for the vapor deposition mask is formed. The dimensions of the rolling material 1b in the width direction DW may be adjusted by cutting after annealing.

In the manufacturing method using electrolysis, the vapor deposition mask base material 1 is formed on the surface of the electrode used for electrolysis, and then the vapor deposition mask base material 1 is released from the surface. At this time, for example, another electrode in which the electrolytic drum electrode having a mirror surface as the surface is immersed in the electrolytic bath and faces the surface of the electrolytic drum electrode is used. Then, when an electric current is passed between the electrolytic drum electrode and another electrode, the vapor deposition mask base material 1 is deposited on the surface of the electrolytic drum electrode. The vapor deposition mask base material 1 is peeled off from the surface of the electrolytic drum electrode at the timing when the vapor deposition mask base material 1 has a desired thickness due to the rotation of the electrolytic drum electrode, and the peeled vapor deposition mask base material 1 is wound up. Be done. In the manufacturing method using electrolysis, the base material 1 for a vapor deposition mask may be manufactured by annealing the metal foil obtained by electrolysis.

When the material forming the substrate 1 for the vapor deposition mask is Invar, the electrolytic bath used for electrolysis includes an iron ion feeder, a nickel ion feeder, and a pH buffer. The electrolytic bath may contain a stress relaxation agent, an Fe ³⁺ ion masking agent, a complexing agent and the like. The electrolysis bath is a weakly acidic solution, and the pH of the electrolysis bath is adjusted to a pH suitable for electrolysis. The iron ion feeder is, for example, ferrous sulfate heptahydrate, ferrous chloride, iron sulfamate, and the like. Nickel ion feeders include, for example, nickel (II) sulfate, nickel (II) chloride, nickel sulfamate, nickel bromide, and the like. The pH buffers are, for example, boric acid and malonic acid. Malonic acid ^{also functions as a Fe 3+} ion masking agent. The stress relaxant is, for example, sodium saccharin. The complexing agent is, for example, malic acid and citric acid. The electrolytic bath is, for example, an aqueous solution containing the above-mentioned additives. The pH of the electrolytic bath is adjusted by, for example, 2 or more and 3 or less by a pH adjusting agent. The pH regulator may be, for example, 5% sulfuric acid and nickel carbonate.

Under the conditions used for electrolysis, the temperature, current density, and electrolysis time of the electrolytic bath are appropriately adjusted according to the thickness of the base material 1 for the vapor deposition mask, the composition ratio of the base material 1 for the vapor deposition mask, and the like. .. The anode applied to the above-mentioned electrolytic bath may be, for example, a pure iron electrode and a nickel electrode. The cathode applied to the above-mentioned electrolytic bath may be, for example, an electrode made of stainless steel, for example, an electrode made of SUS304. The temperature of the electrolytic bath is included in the range of, for example, 40 ° C. or higher and 60 ° C. or lower. The current density is included in the range of ^{1 A / dm 2} or more and 4 A / dm ^{2 or less, for example.}

The thin-film deposition mask base material 1 by electrolysis and the thin-film deposition mask base material 1 by rolling may be further thinned by chemical polishing, electrical polishing, or the like. The polishing liquid used for chemical polishing is, for example, a chemical polishing liquid for iron-based alloys containing hydrogen peroxide as a main component. The electrolytic solution used for electrical polishing is a perchloric acid-based electrolytic polishing solution, a sulfuric acid-based electrolytic polishing solution, or the like.

In the manufacturing method using rolling, a metal oxide having granules is contained in the vapor deposition mask base material 1 in no small amount. Metal oxides include, for example, aluminum oxide and magnesium oxide. When the above-mentioned base material 1a is formed, a deoxidizer having granules is mixed with the raw material in order to prevent oxygen from being mixed into the base material 1a. The deoxidizer is formed of aluminum, magnesium and the like. Then, aluminum and magnesium remain in the base material 1a in no small amount as metal oxides such as aluminum oxide and magnesium oxide. In this regard, according to the production method using electrolysis, since no deoxidizer is used, the metal oxide produced by the oxidation of the deoxidizer is produced from the vapor deposition mask base material 1 and the vapor deposition mask base material 1. It does not mix with 10.

[Manufacturing method of thin-film mask]
A method for manufacturing the vapor deposition mask 10 will be described with reference to FIGS. 9 to 14.
As shown in FIG. 9, when manufacturing the vapor deposition mask 10, first, the substrate 1 for the vapor deposition mask, the first dry film resist (DFR) 2, and the second dry film resist (DFR) 3 are manufactured. And prepare. The base material 1 for a vapor deposition mask includes a front surface 1F and a back surface 1R. Each of DFR2 and 3 is formed separately from the base material 1 for a vapor deposition mask. Next, the first DFR2 is attached to the front surface 1F, and the second DFR3 is attached to the back surface 1R.

As shown in FIG. 10, the first hole 2a is formed in the first DFR2 and the second hole 3a is formed in the second DFR3. At this time, DFRs 2 and 3 are exposed, and DFRs 2 and 3 after exposure are developed. When developing DFRs 2 and 3 after exposure, for example, an aqueous sodium carbonate solution can be used as the developing solution.

As shown in FIG. 11, the back surface 1R of the base material 1 for a vapor deposition mask is etched with a ferric chloride solution using the developed second DFR3 as a mask. At this time, the surface protective layer 4 is formed on the front surface 1F so that the front surface 1F is not etched at the same time as the back surface 1R. The material forming the surface protective layer 4 has chemical resistance to ferric chloride solution. As a result, a small hole 10HS recessed toward the front surface 1F is formed on the back surface 1R.

The etching solution for etching the vapor deposition mask base material 1 may be an acidic etching solution. When the base material 1 for a vapor deposition mask is formed from Invar, the etching solution may be any as long as it is possible to etch Invar. The acidic etching solution is, for example, perchloric acid, hydrochloric acid, sulfuric acid, formic acid, and perchloric acid, hydrochloric acid, sulfuric acid, formic acid, and the like, with respect to a ferric perchloric acid solution or a mixed solution of ferric perchloric acid solution and ferric chloride solution. , Acetic acid is a mixed solution. The method of etching the vapor deposition mask base material 1 may be a dip type in which the vapor deposition mask base material 1 is immersed in an acidic etching solution, or a spray type in which the vapor deposition mask base material 1 is sprayed with an acidic etching solution. It may be.

Next, as shown in FIG. 12, the second DFR3 formed on the back surface 1R and the surface protective layer 4 in contact with the first DFR2 are removed. Further, in order to prevent further etching of the back surface 1R, the back surface protective layer 5 is formed on the back surface 1R. The material forming the back surface protective layer 5 has chemical resistance to ferric chloride solution.

Next, as shown in FIG. 13, the surface 1F is etched with a ferric chloride solution using the developed first DFR2 as a mask. As a result, a large hole 10HL that is recessed from the front surface 1F toward the back surface 1R is formed. The etching solution used at this time is an acidic etching solution. When the base material 1 for a vapor deposition mask is formed from Invar, the etching solution may be any as long as it is possible to etch Invar. The method for etching the vapor deposition mask base material 1 may be the above-mentioned dip type or a spray type.

Next, as shown in FIG. 14, the back surface protective layer 5 and the first DFR2 are removed from the vapor deposition mask base material 1. As a result, a thin-film mask 10 in which a plurality of small holes 10HS and large holes 10HL connected to each small hole 10HS are formed can be obtained. The front surface 1F of the vapor deposition mask base material 1 corresponds to the front surface 10F of the vapor deposition mask 10, and the back surface 1R of the vapor deposition mask base material 1 corresponds to the back surface 10R of the vapor deposition mask 10.

[Example]
[Example 1]
Examples and comparative examples will be described with reference to FIG.

[Evaporation mask]
An Invar sheet having a thickness of 25 μm was prepared. Then, wet etching of the back surface using a resist mask and wet etching of the front surface using a resist mask were performed in the order described. As a result, in the vapor deposition mask described above with reference to FIGS. 3 to 6, the length in the width direction is 70 mm, the length in the length direction is 1250 mm, and the length is along the length direction. A thin-film mask having three pattern regions arranged side by side was formed.

At this time, a large opening having a length of 70 μm in the length direction and the width direction and a small opening having a length of 40 μm in the length direction DL and the width direction DW and lining up at a pitch of 70 μm are provided. A mask hole was formed. 19 such vapor deposition masks were prepared. Arithmetic mean roughness Ra and maximum height Rz were measured for each vapor deposition mask.

[Measuring method]
For the pattern region located in the center in the length direction of each vapor deposition mask, an arithmetic mean roughness Ra conforming to JIS B 0601: 2013 using a 3D measurement laser microscope (OLS5000, manufactured by Olympus Corporation), and , The maximum height Rz of the roughness curve conforming to the same standard was measured. At this time, the cutoff value in the λs contour curve was set to 2.5 μm, and the cutoff value in the λc contour curve filter was set to 250 μm. Further, for each pattern region, the straight line LA described above with reference to FIG. 3 was set at arbitrary three locations. At this time, in the width direction DW, the starting point is a position 5 μm away from the point A1 toward the side opposite to the point A2 with respect to the point A1, and the starting point is 490 μm in the direction from the starting point toward the point A1, that is, 7 pitches apart. The end point was a position further 5 μm away from the above position. As a result, a length of 500 μm along the DW in the width direction was measured. Then, the average value of the three measured values was set to the arithmetic mean roughness Ra in each pattern region and the maximum height Rz of the roughness curve.

[Evaluation method]
The laminated body of the vapor deposition mask and the dust-free paper was housed in a plastic case with each vapor deposition mask sandwiched between two sheets of dust-free paper. Then, a plastic case was placed on the vibration tester, and vibration was applied in the direction perpendicular to the plastic case. At this time, the vapor deposition mask was vibrated for 90 minutes in a method based on the random vibration test of "Packaged cargo-vibration test method" of JIS Z 0232: 2004. Next, the vapor deposition mask was taken out from the plastic case, and the surface of the pattern region located in the center in the length direction in which a plurality of large openings were formed was observed with an optical microscope. As a result, the fibers were counted in 25 different regions. At this time, the size of one region was set to 700 nm × 1000 nm, which is a size at which fibers can be confirmed. Then, the evaluation when the total number of fibers existing in each region exceeds 10 is set to "x", and the evaluation when the total number of fibers is 10 or less is set to "○".

[Measurement results and evaluation results]
The measurement results and the evaluation results were as shown in FIG.
That is, as shown in FIG. 15, it was confirmed that the evaluation result of Comparative Example 1-1 was "x" and the evaluation result of Examples 1-1 to 1-18 was "○". The arithmetic mean roughness Ra of Comparative Example 1-1 whose evaluation result was "x" was 3.22 μm, which was found to exceed 1.35 μm. On the other hand, it was confirmed that the arithmetic mean roughness Ra in Examples 1-1 to 1-18 in which the evaluation result was “◯” was 1.35 μm at the maximum. From these results, it can be said that when the arithmetic mean roughness Ra on the surface of the lattice structure is 1.35 μm or less, the fibers derived from dust-free paper are suppressed from adhering to the vapor deposition mask.

Further, it was found that the maximum height Rz of the roughness curve in Examples 1-1 to 1-18 was 6.79 μm at the maximum. On the other hand, the maximum height Rz of the roughness curve in Comparative Example 1-1 was 11.76 μm, which was found to exceed 6.8 μm. From these results, it can be said that when the maximum height Rz of the roughness curve on the surface of the lattice structure is 6.8 μm or less, fibers derived from dust-free paper are suppressed from adhering to the vapor deposition mask.

As described above, according to the first embodiment of the vapor deposition mask, the effects described below can be obtained.
(1) If the arithmetic average roughness Ra on the front surface 10F of the lattice structure 10M having a large surface roughness is 1.35 μm or less, the adhesion of fibers should be suppressed on both the front surface 10F and the back surface 10R of the lattice structure 10M. Is possible. Further, since the maximum height Rz is 6.8 μm or less, the peak portion located on the surface 10F of the vapor deposition mask 10 has a height that makes it difficult for the fiber to get caught, and the valley portion has a depth that makes it difficult for the fiber to fit. It is possible to have.

(2) Since the top is flat due to the gaps between the large opening HLs located in the diagonal direction of the large opening HL remaining without being etched, the fibers are more difficult to adhere.

The above-described first embodiment can be modified and implemented as follows.
[Lattice structure]
-The top of the lattice structure 10M does not have to be flat. For example, the top of the lattice structure 10M may be convex. Such a convex surface is formed by wet etching the region surrounded by the four large opening HLs in the wet etching for forming the large opening HL. Even in this case, if the arithmetic mean roughness Ra according to JIS B 0601: 2013 at the boundary between the large openings HL adjacent to each other on the surface 10F is 1.35 μm or less, the above-mentioned (1) is applied. You can get the effect.

The surface 10F does not have to have a recess located on the grid line of the lattice structure 10M and a top located on the grid point. That is, in the lattice structure 10M, the lattice lines and the lattice points may be located on the same plane. Even in this case, if the arithmetic mean roughness Ra according to JIS B 0601: 2013 at the boundary between the large openings HL adjacent to each other on the surface 10F is 1.35 μm or less, the above-mentioned (1) is applied. You can get the effect.

[Large opening]
Each large opening HL may be separated from the other large opening HL when viewed from the viewpoint facing the surface 10F. In this case, on the surface 10F, the portion located between the large openings HL remains unetched. As a result, when viewed from the viewpoint facing the surface 10F, the surface 10F contains more flat surfaces than when each large opening HL is in contact with the other large opening HL, so that fibers are less likely to adhere to the surface 10F. ..

[Shape of mask hole]
-The edge of the large opening HL, the edge of the central opening HC, and the edge of the small opening HS may each have a shape other than a substantially square shape. For example, each edge may have a rectangular shape or a polygonal shape other than a rectangular shape. Further, for example, each edge may have a circular shape.

[Second Embodiment]
A second embodiment of the vapor deposition mask will be described with reference to FIGS. 16 to 20. The thin-film deposition mask of the second embodiment has a different shape of mask holes from the thin-film deposition mask of the first embodiment. Therefore, in the following, the differences from the first embodiment will be described in detail in the second embodiment, while the configuration common to the first embodiment in the second embodiment is the same as the reference numerals used in the first embodiment. The detailed description of the configuration will be omitted by adding the reference numerals. Further, in the following, the vapor deposition mask and the examples will be described in order.

[Evaporation mask]
The vapor deposition mask will be described with reference to FIGS. 16 to 19.
FIG. 16 shows a planar structure in a part of the pattern region 10a seen from the viewpoint facing the surface 10F.

As shown in FIG. 16, the lattice structure 20M includes a first lattice line 20M1 having a large line width on the surface 10F and a second lattice line 20M2 having a narrow line width on the surface 10F. On the surface 10F, the first grid line 20M1 and the second grid line 20M2 form a boundary between large opening HLs adjacent to each other.

It is preferable that the vapor deposition mask 10 of the present embodiment further satisfies the following condition 4 in addition to the above-mentioned condition 1.
(Condition 4) The arithmetic mean roughness Ra based on JIS B 0601: 2013 on the first grid line 20M1 is smaller than the arithmetic mean roughness Ra based on JIS B 0601: 2013 on the second grid line 20M2.

Since the arithmetic average roughness Ra of the first grid line 20M1, which has a larger contact area with the dust-free paper than the second grid line 20M2, is smaller than the arithmetic average roughness Ra of the second grid line 20M2, the vapor deposition mask 10 and the dust-free paper It is possible to suppress the adhesion of fibers derived from dust-free paper to the thin-film deposition mask 10 when friction occurs between the two.

It is preferable that the vapor deposition mask 10 of the present embodiment further satisfies the following condition 5.
(Condition 5) On the surface 10F, the arithmetic mean roughness Ra based on JIS B 0601: 2013 at the first grid line 20M1 is 0.14 μm or less, and JIS B 0601: 2013 at the second grid line 20M2. The conforming arithmetic mean roughness Ra is 1.3 μm or less.

When the vapor deposition mask 10 satisfies the condition 5, fibers derived from dust-free paper are further suppressed from adhering to the vapor deposition mask 10.
The arithmetic mean roughness Ra under the conditions 4 and 5 is the contour curve obtained when the cutoff value in the λs contour curve filter is set to 2.5 μm and the cutoff value in the λc contour curve filter is set to 80 μm. Is the arithmetic mean roughness of the roughness curve.

Each mask hole 20H has a large opening HL and a central opening HC, similar to the mask hole 10H of the first embodiment described above. In the mask hole 20H, the cross-sectional area along the plane parallel to the surface 10F gradually decreases along the direction from the large opening HL to the central opening HC. In the mask hole 20H, the portion from the large opening HL to the central opening HC has an inverted pyramid shape when viewed from the viewpoint facing the surface 10F.

In this embodiment, the edge of each large opening HL has a diamond shape. At the edge of the large opening HL, the two corners adjacent to each other in the length direction DL have a curvature such that the center of curvature is located inside the large opening HL. Further, at the edge of the large opening HL, the two corners adjacent to each other in the width direction DW have a curvature such that the center of curvature is located inside the large opening HL. At the edge of the large opening HL, the curvature at the pair of corners adjacent to each other in the length direction DL is larger than the curvature at the pair of corners adjacent to each other in the width direction DW. On the other hand, the edge of each central opening HC has a substantially square shape.

Each of the first grid line 20M1 and the second grid line 20M2 includes a part of the surface 10F. In the lattice structure 20M, two second lattice lines 20M2 are connected to each end of one first lattice line 20M1. On the other hand, one first grid line 20M1 is connected to each end of one second grid line 20M2.

When viewed from the viewpoint facing the surface 10F, the first grid line 20M1 and the large opening HL are alternately arranged in the width direction DW, and the second grid line 20M2 and the large opening HL are alternately arranged in the direction intersecting the width direction DW. They are lined up.

On the surface 10F of the vapor deposition mask 10, a straight line LB along the width direction DW of the vapor deposition mask 10 and a straight line extending along a direction intersecting the length direction DL are used to measure the height profile of the vapor deposition mask 10. LC is set. The straight line LB is located on one first lattice line 20M1 included in the lattice structure 20M. The straight line LB is a straight line connecting the points B1 and B2. The direction from the point B1 to the point B2 is the first direction DB in which the straight line LB extends. The straight line LC is located on one second lattice line 20M2 included in the lattice structure 20M. The straight line LC is a straight line connecting the points C1 and C2. The direction from the point C1 to the point C2 is the second direction DC in which the straight line LC extends.

FIG. 17 shows a planar structure in a part of the pattern region 10a seen from the viewpoint facing the back surface 10R.
As shown in FIG. 17, each mask hole 20H has a small opening HS that opens to the back surface 10R. The small opening HS has a substantially square shape when viewed from a viewpoint facing the back surface 10R. In the mask hole 20H, the cross-sectional area along the plane parallel to the back surface 10R gradually decreases along the direction from the small opening HS to the central opening HC. In the mask hole 20H, the portion from the small opening HS to the central opening HC has an inverted weight stand shape when viewed from the viewpoint corresponding to the back surface 10R.

FIG. 18 shows the height profile of the vapor deposition mask 10 along the first grid line 20M1 on the surface 10F of the vapor deposition mask 10. FIG. 19 shows the height profile of the vapor deposition mask 10 along the second grid line 20M2 on the surface 10F of the vapor deposition mask 10. In FIGS. 18 and 19, for convenience of explaining the height profile of the surface 10F, the height difference included in the height profile is exaggerated. The broken lines shown in FIGS. 18 and 19 indicate the average height of the surface 10F in the region targeted for analysis of the height profile.

The height profile shown in FIG. 18 is a height profile along a straight line LB connecting the points B1 and B2 in FIG. The straight line LB is located on one first lattice line 20M1 included in the lattice structure 10M. Each point B1 and B2 is surrounded by three large openings HL when viewed from a viewpoint facing the surface 10F of the vapor deposition mask 10. Each point B1 and B2 is located in a region surrounded by a corner portion of each large opening HL. This region is a region where the etching solution does not easily wrap around during wet etching of the substrate for the vapor deposition mask. On the other hand, the region located between the points B1 and B2 is a region sandwiched by two large opening HLs. Therefore, the region is a region in which the etching solution is more likely to wrap around during wet etching of the substrate for the vapor deposition mask, as compared with the region where the points B1 and B2 are located.

Therefore, as shown in FIG. 18, the height profile in the straight line LB has a maximum value at each point B1 and B2. On the other hand, the height profile in the straight line LB has a minimum value at a position where the distances from the points B1 and B2 are almost equal.

The height profile shown in FIG. 19 is a height profile along a straight line LC connecting the points C1 and C2 in FIG. Each point C1 and C2 is surrounded by three large openings HL when viewed from a viewpoint facing the surface 10F of the vapor deposition mask 10. Each point C1 and C2 is located in a region surrounded by a corner portion of each large opening HL. This region is a region where the etching solution does not easily wrap around during wet etching of the substrate for the vapor deposition mask. On the other hand, the region located between the points C1 and C2 is the region sandwiched by the two large opening HLs. Therefore, the region is a region in which the etching solution is more likely to wrap around during wet etching of the substrate for the vapor deposition mask, as compared with the region where the points C1 and C2 are located.

Therefore, as shown in FIG. 19, the height profile in the straight line LC has a maximum value at each point C1 and C2. On the other hand, the height profile in the straight line LC has a minimum value at a position where the distances from the points C1 and C2 are almost equal. The height at each point C1 and C2 is higher than the height at each point B1 and B2.

[Example]
[Example 2]
Examples and comparative examples will be described with reference to FIG.

[Evaporation mask]
An Invar sheet having a thickness of 25 μm was prepared. Then, wet etching of the back surface using a resist mask and wet etching of the front surface using a resist mask were performed in the order described. As a result, in the vapor deposition mask described above with reference to FIGS. 16 to 19, the length in the width direction is 70 mm, the length in the length direction is 1250 mm, and the length is along the length direction. A thin-film mask having three pattern regions arranged side by side was formed.

At this time, a plurality of mask holes were formed so that the plurality of mask holes were arranged in a staggered arrangement. Further, a mask hole was formed in a small opening having a length of 40 μm in the width direction and the length direction so that the pitch in the length direction was 85 μm and the pitch in the width direction was 100 μm. Further, a large diamond-shaped opening having a length of 75 μm in the length direction and a length of 70 μm in the width direction has a pitch of 85 μm in the length direction and a pitch of 70 μm in the width direction. Mask holes were formed so as to be 100 μm. Seventeen such vapor deposition masks were prepared. In each vapor deposition mask, the arithmetic mean roughness Ra and the maximum height Rz were measured for each of the first grid line and the second grid line.

[Measuring method]
For the pattern region located in the center in the length direction of each vapor deposition mask, an arithmetic mean roughness Ra conforming to JIS B 0601: 2013 using a 3D measurement laser microscope (OLS5000, manufactured by Olympus Corporation), and , The maximum height Rz of the roughness curve conforming to the same standard was measured. At this time, the cutoff value in the λs contour curve was set to 2.5 μm, and the cutoff value in the λc contour curve filter was set to 80 μm. Further, for the first grid line of each pattern region, any length included in the range of 33 μm or more and 48 μm or less was measured at three points, and the average value was set as the measurement result in the first grid line. For the second grid line of each pattern region, any length included in the range of 60 μm or more and 68 μm or less was measured at three points, and the average value was set as the measurement result in the second grid line. In FIG. 20 referred to below, the case where the measurement point is the first grid line is referred to as “LB”, and the case where the measurement point is the second grid line is referred to as “LC”.

[Evaluation method]
The laminated body of the vapor deposition mask and the dust-free paper was housed in a plastic case with each vapor deposition mask sandwiched between two sheets of dust-free paper. Then, a plastic case was placed on the vibration tester, and vibration was applied in the direction perpendicular to the plastic case. At this time, the vapor deposition mask was vibrated for 90 minutes in a method based on the random vibration test of "Packaged cargo-vibration test method" of JIS Z 0232: 2004. Next, the vapor deposition mask was taken out from the plastic case, and the surface of the pattern region located in the center in the length direction in which a plurality of large openings were formed was observed with an optical microscope. As a result, the fibers were counted in 25 different regions. At this time, the size of one region was set to 700 nm × 1000 nm, which is a size at which fibers can be confirmed. Then, the evaluation when the total number of fibers existing in each region exceeds 10 is set to "x", and the evaluation when the total number of fibers is 10 or less is set to "○".

[Measurement results and evaluation results]
The measurement results and the evaluation results were as shown in FIG.
That is, as shown in FIG. 20, it was confirmed that the evaluation result of Comparative Example 2-1 was “x” and the evaluation result of Examples 2-1 to 2-16 was “◯”. In Comparative Example 2-1 in which the evaluation result is "x", the arithmetic mean roughness Ra of the first grid line is 2.32 μm, and the arithmetic mean roughness Ra of the second grid line is 2.11. Admitted. That is, it was found that the arithmetic mean roughness Ra exceeded 1.35 μm in both the first grid line and the second grid line. On the other hand, the arithmetic mean roughness Ra of Examples 2-1 to 2-16 whose evaluation result is "○" is 1.27 μm at the maximum in both the first grid line and the second grid line. Was recognized as. From these results, it can be said that when the arithmetic mean roughness Ra on the surface of the lattice structure is 1.35 μm or less, the fibers derived from dust-free paper are suppressed from staying on the vapor deposition mask.

Further, it was found that the maximum height Rz of the roughness curve in Examples 2-1 to 2-16 was 1.61 μm at the maximum. On the other hand, the maximum height Rz of the roughness curve in Comparative Example 2-1 was 7.89 μm at the minimum, which was found to exceed 6.8 μm. From these results, it can be said that when the maximum height Rz of the roughness curve on the surface of the lattice structure is 6.8 μm or less, fibers derived from dust-free paper are suppressed from adhering to the vapor deposition mask.

As described above, according to the second embodiment of the vapor deposition mask, the effects described below can be obtained.
(3) Since the arithmetic average roughness Ra of the first grid line 20M1 having a larger contact area with the dust-free paper than the second grid line 20M2 is smaller than the arithmetic average roughness Ra of the second grid line 20M2, the vapor deposition mask 10 When friction occurs between the dust-free paper and the dust-free paper, it is possible to suppress the adhesion of fibers derived from the dust-free paper to the vapor deposition mask 10.

The above-mentioned second embodiment can be modified and implemented as follows.
[Lattice structure]
-The top of the lattice structure 10M does not have to be flat. For example, the top of the lattice structure 10M may be a convex surface protruding toward the side opposite to the back surface 10R. Even in this case, if the arithmetic mean roughness Ra according to JIS B 0601: 2013 at the boundary between the large openings HL adjacent to each other on the surface 10F is 1.35 μm or less, the above-mentioned (1) is applied. You can get the effect.

The arithmetic average roughness Ra of the first grid line 20M1 may be equal to or greater than the arithmetic average roughness Ra of the second grid line 20M2. Even in this case, if the arithmetic mean roughness Ra according to JIS B 0601: 2013 at the boundary between the large openings HL adjacent to each other on the surface 10F is 1.35 μm or less, the above-mentioned (1) is applied. You can get the effect.

[Shape of mask hole]
-The edge of the large opening HL may have a shape other than the diamond shape. The edge of the large opening HL may have a polygonal shape other than a rhombus, or may have a circular shape. Further, the edge of the central opening HC and the edge of the small opening HS may have a shape other than a substantially square shape. Each edge may have a rectangular shape or a polygonal shape other than a rectangular shape. Further, for example, each edge may have a circular shape.

10 ... Vapor deposition mask 10a ... Pattern area 10b ... Peripheral area 10F ... Front surface 10H, 20H ... Mask holes 10M, 20M ... Lattice structure 10R ... Back surface 20M1 ... First lattice line 20M2 ... Second lattice line HC ... Central opening HL ... Large opening HS ... Small opening

Claims (4)

A metal vapor deposition mask
A lattice structure having a front surface and a back surface, the lattice structure having a two-dimensional mesh shape that separates a plurality of mask holes connecting a large opening located on the front surface and a small opening located on the back surface. Prepare,
Large openings adjacent to each other on the surface are in contact with each other at a part of the edge.
JIS in the range where two or more sets of boundaries of one set of large openings adjacent to each other on the surface are continuous
The arithmetic mean roughness Ra according to B 0601: 2013 is 1.35 μm or less.
The maximum height Rz in accordance with JIS B 0601: 2013 in the above range is 6.8 μm or less.
A thin-film mask in which the surface roughness at the boundary is larger than the surface roughness at the back surface. The surface is
The depressions located on the lattice lines of the lattice structure and
It is provided with a top, which is located at a lattice point of the lattice structure and is a portion where the depressions are connected to each other.
The vapor deposition mask according to claim 1, wherein the recess and the top form the boundary. The vapor deposition mask according to claim 2, wherein the top is flat. The lattice structure includes a first lattice line having a large line width on the surface and a second lattice line having a narrow line width on the surface.
The first grid line and the second grid line exist in the above range,
The arithmetic mean roughness Ra based on JIS B 0601: 2013 on the surface is higher than the arithmetic mean roughness Ra based on JIS B 0601: 2013 on the surface. The small vapor deposition mask according to claim 1.

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